fix: fix image artifact regex to match GitHub Actions filename (#1013)

GitHub Actions doesn't allow artifact files to contain `:`, so it is
replaced with `---`. Update this artifact finding code to match that
pattern.

bioconda_utils/artifacts.py

@@ -18,7 +18,7 @@
 logger = logging.getLogger(__name__)
 
 
-IMAGE_RE = re.compile(r"(.+)(?::|%3A)(.+)\.tar\.gz$")
+IMAGE_RE = re.compile(r"(.+)(?::|%3A|---)(.+)\.tar\.gz$")
 
 
 class UploadResult(Enum):